Yep , that would work though I personaly would choose another case than the Dakota. the 300 win mag would be great ,you could use Lapua bras for about the same cost as the Dakota and it will last longer. and the 280 can be reamed to 7mm-300 win mag and that would actualy be a step op from the Dakota again with better brass.
that action is plenty strong enough and those barrels are perfect.
I would say that the 7-300 win mag would be right around the 7STW range maybe a bit more with the better brass and slightly shorter OAL, definatly a set up from the 7mmRem mag.
The 300 Win mag isin't that big of a step behind the 300 Dakota if any at all , in fact I think that with Lapua brass the 300 win would out run the 300 Dakota